Plastic depolymerization device

Abstract

The utility model relates to the technical field of plastic degradation, and provides a plastic depolymerization device which comprises a reaction container, a microwave generation mechanism and an electromagnetic induction generation mechanism, the reaction container is provided with a containing cavity, and the containing cavity contains a mixture of plastic to be treated and liquid metal; the microwave generating mechanism emits microwaves with a first preset frequency into the containing cavity, and the microwaves enable the liquid metal to generate arc discharge so as to ionize gas in the containing cavity to form plasma; and the electromagnetic induction generating mechanism emits an alternating magnetic field with a second preset frequency into the containing cavity, the second preset frequency is smaller than the first preset frequency, and the alternating magnetic field enables the liquid metal in the containing cavity to generate eddy current. Through the arrangement, the plasma instantly destroys a plastic molecular structure, so that a plastic molecular chain is preliminarily broken, heat generated by the eddy current effect is combined with the heat-conducting property of the liquid metal to quickly and uniformly increase the temperature, the breakage of the plastic molecular chain is further promoted, and the plastic depolymerization efficiency and sufficiency are greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of plastic degradation technology, and in particular to a plastic depolymerization device. Background Technology

[0002] With global economic development and rising living standards, the consumption of plastic products has been increasing year by year. However, due to the non-degradable nature of plastics, serious environmental pollution problems have arisen, especially marine plastic pollution. Traditional methods of plastic waste disposal mainly include landfill and incineration. Landfill disposal not only occupies a large amount of land resources but may also lead to soil and groundwater pollution. While incineration can reduce volume, it produces harmful gases such as dioxins.

[0003] Currently, pyrolysis technology, as a relatively advanced method for treating waste plastics, decomposes plastics into smaller molecules by heating them in an oxygen-free or low-oxygen environment, primarily through controlling conditions such as temperature, pressure, and reaction time. Related technologies require a heat source above the melting temperature of the waste plastics to heat them; the plastics absorb heat, their temperature rises, and they pyrolyze. This results in low energy utilization and low pyrolysis efficiency. Furthermore, the poor thermal conductivity of waste plastics leads to uneven heating and incomplete pyrolysis.

[0004] Therefore, how to solve the problems of low pyrolysis efficiency and incomplete pyrolysis in the pyrolysis of waste plastics in related technologies has become an important technical problem to be solved by those skilled in the art. Utility Model Content

[0005] This invention provides a plastic depolymerization device to solve the defects of low pyrolysis efficiency and insufficient pyrolysis in related technologies when pyrolyzing waste plastics.

[0006] This utility model provides a plastic depolymerization device, comprising:

[0007] A reaction vessel having a containment chamber adapted to contain a mixture of plastic and liquid metal to be treated;

[0008] A microwave generating mechanism is adapted to emit microwaves of a first preset frequency into the containment chamber of the reaction vessel, the microwaves being adapted to cause an electric arc discharge in the liquid metal within the containment chamber of the reaction vessel, thereby ionizing the gas within the containment chamber of the reaction vessel to form plasma;

[0009] An electromagnetic induction generating mechanism is adapted to emit an alternating magnetic field of a second preset frequency into the containment chamber of the reaction vessel, the second preset frequency being less than the first preset frequency, and the alternating magnetic field being adapted to induce eddies in the liquid metal within the containment chamber of the reaction vessel.

[0010] According to the plastic depolymerization device provided by this utility model, the microwave generating mechanism includes:

[0011] A microwave generator, adapted to generate microwaves at the first preset frequency, is disposed outside the reaction vessel;

[0012] A waveguide transmission assembly is disposed between the microwave generator and the reaction vessel, and the waveguide transmission assembly is adapted to transmit the microwaves generated by the microwave generator to the receiving chamber of the reaction vessel.

[0013] According to the plastic depolymerization device provided by this utility model, the electromagnetic induction generating mechanism includes:

[0014] An induction coil is arranged around the outside of the containing chamber of the reaction vessel;

[0015] A power source is electrically connected to the induction coil, and the power source is adapted to input alternating current into the induction coil.

[0016] According to the plastic depolymerization device provided by this utility model, the first preset frequency is 300 MHz to 300 GHz, and the second preset frequency is 20 kHz to 300 kHz.

[0017] According to the plastic depolymerization device provided by this utility model, it further includes:

[0018] A pretreatment facility adapted to pretreat the plastic to be treated, the pretreatment including at least one of crushing, washing and drying.

[0019] According to the plastic depolymerization device provided by this utility model, it further includes:

[0020] A condensation mechanism is connected to the receiving chamber of the reaction vessel, and the condensation mechanism is adapted to condense condensable gases in the gaseous products output from the receiving chamber of the reaction vessel into liquids or solids.

[0021] A gas collection mechanism is connected to the condensation mechanism, and the gas collection mechanism is adapted to collect non-condensable gases in the gaseous products;

[0022] A solid-liquid separation mechanism is connected to the receiving chamber of the reaction vessel, and the solid-liquid separation mechanism is adapted to separate solid and liquid substances in the non-gaseous substances within the receiving chamber of the reaction vessel.

[0023] According to the plastic depolymerization device provided by this utility model, it further includes:

[0024] A liquid metal supply mechanism is connected to the containment chamber of the reaction vessel, and the liquid metal supply mechanism is adapted to supply the liquid metal to the containment chamber of the reaction vessel.

[0025] According to the plastic depolymerization device provided by this utility model, the liquid metal supply mechanism includes:

[0026] A spray head is disposed at the top of the receiving chamber of the reaction vessel;

[0027] A liquid metal storage tank, suitable for containing the liquid metal, is connected to the spray head via a connecting pipe;

[0028] A power pump is installed in the connecting pipeline, and the power pump is adapted to pump the liquid metal in the liquid metal storage tank to the spray head;

[0029] A flow meter is installed in the connecting pipeline, and the flow meter is adapted to measure the flow rate of the liquid metal in the connecting pipeline.

[0030] According to the present invention, a plastic depolymerization device is provided in the reaction vessel, wherein a stirring mechanism is provided, and the stirring mechanism is adapted to stir the mixture of the plastic to be treated and the liquid metal.

[0031] According to the plastic depolymerization device provided by this utility model, it further includes:

[0032] A temperature sensing element is disposed in the reaction vessel, and the temperature sensing element is adapted to detect the temperature inside the containment chamber of the reaction vessel;

[0033] A pressure detection element is disposed in the reaction vessel, the pressure detection element being adapted to detect the pressure within the containment chamber of the reaction vessel;

[0034] The controller is electrically connected to the temperature detection element, the pressure detection element, the microwave generating mechanism, and the electromagnetic induction generating mechanism. The controller is adapted to control the operation of the microwave generating mechanism and the electromagnetic induction generating mechanism according to the temperature and pressure inside the containment chamber of the reaction vessel.

[0035] The plastic depolymerization device provided by this utility model includes a reaction container, a microwave generating mechanism, and an electromagnetic induction generating mechanism. The reaction container has a receiving chamber for containing a mixture of the plastic to be treated and liquid metal. The liquid metal and the plastic to be treated are mixed uniformly. The liquid metal has excellent thermal conductivity, and its uniform distribution among the plastics facilitates uniform heating of the plastics. The microwave generating mechanism emits microwaves of a first preset frequency into the receiving chamber of the reaction container. The microwaves of the first preset frequency can cause an arc discharge in the liquid metal within the receiving chamber of the reaction container, thereby ionizing the gas within the receiving chamber of the reaction container to form plasma. The high temperature and highly active plasma generated by the plasma interact with the plastic molecules, instantly destroying the plastic molecular structure, reducing the activation energy of the depolymerization reaction, and causing the plastic molecular chains to initially break. The electromagnetic induction generating mechanism emits an alternating magnetic field of a second preset frequency into the receiving chamber of the reaction container. The second preset frequency is lower than the first preset frequency. The alternating magnetic field of the second preset frequency can induce eddies in the liquid metal within the reaction vessel's containment chamber. Based on the eddy current effect, a large amount of heat is generated, rapidly raising the temperature of the plastic to be treated, thereby further promoting the breaking of plastic molecular chains and the depolymerization reaction. This setup, with the synergistic effect of the microwave of the first preset frequency and the alternating magnetic field of the second preset frequency, significantly improves the depolymerization efficiency of the plastic. Furthermore, the excellent thermal conductivity of the liquid metal, and its uniform distribution among the plastics to be treated, facilitates even heating and thorough depolymerization, solving the problems of low pyrolysis efficiency and incomplete pyrolysis in related technologies for pyrolyzing waste plastics. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the plastic depolymerization device provided by this utility model.

[0038] Figure 2 This is a flowchart of the plastic depolymerization method applicable to the plastic depolymerization device provided by this utility model.

[0039] Figure label:

[0040] 1. Reaction vessel; 2. Microwave generator; 3. Waveguide transmission assembly; 4. Induction coil; 5. Pretreatment mechanism; 6. Condensation mechanism; 7. Controller; 8. Gas collection mechanism; 9. Solid-liquid separation mechanism; 10. Spray head; 11. Temperature detection element; 12. Pressure detection element. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0042] The following is combined Figures 1 to 2 This invention describes a plastic depolymerization device.

[0043] like Figures 1 to 2 As shown, the plastic depolymerization device provided in this embodiment of the present invention includes a reaction vessel 1, a microwave generating mechanism, and an electromagnetic induction generating mechanism.

[0044] Specifically, the reaction vessel 1 has a containment chamber for containing a mixture of the plastic to be treated and the liquid metal.

[0045] The liquid metal is mixed evenly with the plastic to be treated. The liquid metal has excellent thermal conductivity, and its uniform distribution among the plastics is beneficial for the uniform heating of the plastics.

[0046] The microwave generator emits microwaves of a first preset frequency into the containment chamber of the reaction vessel 1. These microwaves cause an electric arc discharge in the liquid metal within the containment chamber, thereby ionizing the gas within the containment chamber to form plasma. The high temperature and high activity of the plasma, combined with the interaction between the plasma and the plastic molecules, instantly overcome the reaction limit of plastic depolymerization, destroying the plastic molecular structure, lowering the activation energy of the depolymerization reaction, and causing the plastic molecular chains to initially break.

[0047] The electromagnetic induction generating mechanism is used to emit an alternating magnetic field of a second preset frequency into the containment chamber of the reaction vessel 1. The second preset frequency is lower than the first preset frequency. The alternating magnetic field of the second preset frequency can generate eddy currents in the liquid metal within the containment chamber of the reaction vessel 1. Based on the eddy current effect, a large amount of heat is generated, which can quickly raise the temperature of the plastic to be processed, thereby further promoting the breaking and depolymerization reaction of the plastic molecular chains.

[0048] This configuration, through the synergistic effect of microwaves at a first preset frequency and alternating magnetic fields at a second preset frequency, significantly improves the depolymerization efficiency of plastics. Furthermore, the excellent thermal conductivity of liquid metal, and its uniform distribution among the plastics being treated, promotes even heating and thorough depolymerization, thus resolving the issues of low pyrolysis efficiency and incomplete pyrolysis in related technologies for treating waste plastics.

[0049] Once the depolymerization process is complete, the depolymerization products can be collected and separated to obtain products that can be utilized as resources, such as light fuel oil, combustible gas, and solid carbon.

[0050] It should be noted that the aforementioned reaction vessel 1 needs to possess excellent electromagnetic wave penetration, high temperature resistance, and corrosion resistance to ensure the effective transmission of electromagnetic waves such as microwaves and alternating magnetic fields and the smooth progress of the reaction. The reaction vessel 1 is a closed structure, requiring the sealing of the containing chamber. During the depolymerization reaction, the reaction vessel 1 needs to be filled with inert gases such as argon and nitrogen.

[0051] In other embodiments, microwave heating or electromagnetic induction heating of liquid metal is used to pyrolyze the plastic. However, using microwave heating alone suffers from low energy efficiency, a relatively slow reaction rate, and difficulty in achieving ideal depolymerization results quickly when processing high-melting-point plastics with complex macromolecular structures. Using electromagnetic induction heating of liquid metal alone leads to uneven heating due to the poor thermal conductivity of plastics, resulting in incomplete depolymerization and unstable product quality. Furthermore, electromagnetic induction heating alone cannot effectively activate plastic molecules or lower the activation energy of the depolymerization reaction.

[0052] The plastic depolymerization device provided in this embodiment of the invention can coordinate the heating technologies of two electromagnetic waves—microwaves of a first preset frequency and alternating magnetic fields of a second preset frequency—combined with the unique properties of liquid metal, to achieve efficient, rapid, and thorough depolymerization of plastics, improving the quality and resource utilization value of the depolymerization products while reducing energy consumption and environmental pollution during the process. Through comparative experiments, the plastic depolymerization device provided in this embodiment of the invention can improve the depolymerization efficiency of plastics. Compared with technical solutions that only use microwave heating to pyrolyze plastics or only use electromagnetic induction heating of liquid metal to pyrolyze plastics, the depolymerization time can be shortened by 30% to 50%.

[0053] In this embodiment of the invention, the microwave generating mechanism includes a microwave generator 2 and a waveguide transmission component 3.

[0054] Microwave generator 2 is used to generate microwaves at a first preset frequency, and microwave generator 2 is disposed outside reaction vessel 1. Waveguide transmission assembly 3 is disposed between microwave generator 2 and reaction vessel 1, and waveguide transmission assembly 3 is used to transmit the microwaves generated by microwave generator 2 to the receiving chamber of reaction vessel 1.

[0055] This design avoids contact with substances such as plastics and liquid metals to be processed, which helps to ensure a stable working environment for the microwave generator 2 and improves its service life.

[0056] In this embodiment of the invention, the electromagnetic induction generating mechanism includes an induction coil 4 and a power supply.

[0057] An induction coil 4 is arranged in a ring around the outside of the containment chamber of the reaction vessel 1. A power supply is electrically connected to the induction coil 4, and the power supply is used to input alternating current into the induction coil 4. When alternating current is passed into the induction coil 4, it causes the induction coil 4 to generate an alternating magnetic field.

[0058] In this embodiment of the invention, the first preset frequency is 300 MHz to 300 GHz, and the second preset frequency is 20 kHz to 300 kHz. The symbol for kHz is kHz, the symbol for MHz is MHz, and the symbol for GHz is GHz.

[0059] Specifically, the first preset frequency can be set to 2.45 gigahertz, and the second preset frequency can be set to 50 kilohertz, 60 kilohertz, 70 kilohertz, or 80 kilohertz.

[0060] In this embodiment of the invention, the plastic depolymerization device further includes a pretreatment mechanism 5, which is used to pretreat the plastic to be treated so that the plastic to be treated reaches a suitable reaction state.

[0061] The pretreatment includes at least one of crushing, washing and drying.

[0062] When crushing the plastic to be processed, a crusher can be used to crush it, so that the particle size of the plastic to be processed is less than 5 mm.

[0063] When cleaning plastics, you can use an ultrasonic cleaner with water as the cleaning solution to ensure that impurities are removed from the surface of the plastic.

[0064] When drying the plastic to be treated, a drying oven can be used. Place the plastic to be treated in a drying oven at 80 degrees Celsius to remove the water from the surface of the plastic.

[0065] In a further embodiment, the plastic depolymerization device also includes a condensation mechanism 6, a gas collection mechanism 8, and a solid-liquid separation mechanism 9.

[0066] The condensation mechanism 6 is connected to the containment chamber of the reaction vessel 1. After the plastic to be treated depolymerizes, gaseous products and solid products are formed. As the depolymerization reaction proceeds, the gaseous products gradually enter the condensation mechanism 6, while non-gaseous substances such as liquid metal and solid products remain in the containment chamber of the reaction vessel 1.

[0067] The gaseous products include condensable gases and non-condensable gases. Condensable gases can condense into liquids or solids upon cooling, while non-condensable gases will not condense into liquids or solids upon cooling. The condensation mechanism 6 enables the condensable gases in the gaseous products output from the containment chamber of the reaction vessel 1 to condense into liquids or solids. The liquids or solids formed by the condensation of the condensable gases remain in the condensation mechanism 6, and the gas collection mechanism 8 is used to collect the remaining non-condensable gases in the gaseous products.

[0068] The solid-liquid separation mechanism 9 is connected to the containment chamber of the reaction vessel 1. After the depolymerization reaction is completed, the non-gaseous substances will enter the solid-liquid separation mechanism 9. The solid-liquid separation mechanism 9 can separate the solid and liquid substances in the non-gaseous substances in the containment chamber of the reaction vessel 1.

[0069] Specifically, a filter can be selected as the solid-liquid separation mechanism 9 to separate solid and liquid substances in non-gaseous substances through filtration. The solid substances in the non-gaseous substances remain in the solid-liquid separation mechanism 9, while the liquid substances are discharged from the solid-liquid separation mechanism 9.

[0070] The solid substance here is solid carbon, and the liquid substance here is liquid metal.

[0071] In this embodiment of the invention, the plastic depolymerization device further includes a liquid metal supply mechanism, which is connected to the receiving chamber of the reaction vessel 1. The liquid metal supply mechanism is used to supply liquid metal to the receiving chamber of the reaction vessel 1. The amount of liquid metal added can be precisely controlled through the liquid metal supply mechanism.

[0072] Specifically, the liquid metal supply mechanism includes a spray head 10, a liquid metal storage tank, a power pump, and a flow meter.

[0073] A spray head 10 is located at the top of the containment chamber of the reaction vessel 1. A liquid metal storage tank is used to contain liquid metal and is connected to the spray head 10 via a connecting pipe. A power pump is installed on the connecting pipe between the liquid metal storage tank and the spray head 10, and is used to pump the liquid metal from the liquid metal storage tank to the spray head 10. A flow meter is installed on the connecting pipe to measure the flow rate of the liquid metal in the connecting pipe, thereby determining the mass of the liquid metal.

[0074] After the pretreated plastic to be treated is added into the containment chamber of reaction vessel 1, liquid metal is added into the containment chamber of reaction vessel 1 by spraying, which is beneficial to the uniform distribution of liquid metal in the containment chamber of reaction vessel 1.

[0075] The liquid metal storage tank of the liquid metal supply mechanism can be connected to the liquid substance outlet of the solid-liquid separation mechanism 9. After depolymerization, the separated liquid metal can be recycled to the liquid metal supply mechanism and transported back to the containment chamber of the reaction vessel 1 for reuse in the depolymerization of the plastic to be treated.

[0076] In this embodiment of the present invention, a stirring mechanism is provided in the reaction vessel 1. The stirring mechanism is used to stir the mixture of the plastic to be treated and the liquid metal so as to make the plastic to be treated and the liquid metal mixed evenly.

[0077] When spraying liquid metal into reaction vessel 1, stirring can be carried out simultaneously. After the addition of liquid metal is complete, stirring can also be performed during the depolymerization reaction.

[0078] In this embodiment of the invention, the plastic depolymerization device further includes a temperature detection element 11, a pressure detection element 12, and a controller 7. The temperature detection element 11, the pressure detection element 12, the microwave generating mechanism, and the electromagnetic induction generating mechanism are all electrically connected to the controller 7.

[0079] Temperature sensing element 11 is disposed in reaction vessel 1, and is used to detect the temperature inside the containment chamber of reaction vessel 1. Pressure sensing element 12 is disposed in reaction vessel 1, and is used to detect the pressure inside the containment chamber of reaction vessel 1.

[0080] The controller 7 is used to control the operation of the microwave generating mechanism and the electromagnetic induction generating mechanism according to the temperature and pressure inside the containment chamber of the reaction vessel 1. Specifically, it can control the power and working time of the microwave generating mechanism and the electromagnetic induction generating mechanism to control the temperature and pressure inside the containment chamber of the reaction vessel 1 within a preset range, so that the depolymerization reaction can proceed efficiently.

[0081] The temperature sensing element 11 may be selected from, but is not limited to, a temperature sensor, and the pressure sensing element 12 may be selected from, but is not limited to, a pressure sensor.

[0082] The plastic to be treated may be, but is not limited to, polyethylene terephthalate (PET or PETE), polypropylene (PP), polyvinyl chloride (PVC), or a hybrid plastic whose main components are polystyrene (PS) and polyurethane (PU).

[0083] When depolymerizing PET plastic, it is first pretreated. Specifically, the PET plastic is first crushed to make the particle size less than 5 mm; then it is washed with clean water to remove impurities from its surface; then it is placed in a drying oven at 80 degrees Celsius for two hours to obtain pretreated PET plastic.

[0084] Then, pretreated PET plastic and liquid gallium indium tin (CITi) metal were added to the containment chamber of reaction vessel 1, with a mass ratio of PET plastic to CITi liquid metal of 5:1. The microwave generator and electromagnetic induction generator were activated, enabling the microwave generator to produce 2.45 GHz microwaves, with its power adjusted to 1000 watts (W). The electromagnetic induction generator was also activated to produce a 50 kHz alternating magnetic field, with its power adjusted to 800 watts. The 2.45 GHz microwaves caused an arc discharge in the CITi liquid metal within the containment chamber of reaction vessel 1, thereby ionizing the gas within the containment chamber to form plasma. Simultaneously, the 50 kHz alternating magnetic field induced eddy currents in the liquid metal within the containment chamber of reaction vessel 1. The high temperature generated by plasma and the interaction between plasma and plastic molecules can instantly destroy the structure of plastic molecules, reduce the activation energy of depolymerization reaction, and cause the plastic molecular chains to break initially. The eddy current effect generates a large amount of heat, which can quickly raise the temperature of the plastic to be treated, thereby further promoting the breaking of plastic molecular chains and the depolymerization reaction.

[0085] During the depolymerization reaction, temperature sensing element 11 and pressure sensing element 12 monitor the temperature and pressure inside the containment chamber of reaction vessel 1 in real time. Controller 7 controls the power and operating time of the microwave generator and electromagnetic induction generator based on the temperature and pressure inside the containment chamber of reaction vessel 1, thereby controlling the temperature inside the containment chamber of reaction vessel 1 at approximately 650 degrees Celsius and the pressure inside the containment chamber of reaction vessel 1 at 0.5 MPa. After the depolymerization reaction has continued for 30 minutes, the microwave generator and electromagnetic induction generator are turned off, stopping the depolymerization reaction.

[0086] During the depolymerization reaction, the gaseous products gradually enter the condensation mechanism 6, while the non-gaseous substances remain in the containment chamber of the reaction vessel 1. When the gaseous products pass through the condensation mechanism 6, condensable gases condense into solids and remain in the condensation mechanism 6, while non-condensable gases can flow to the gas collection mechanism 8, thus separating the condensable and non-condensable gases from the gaseous products. Testing showed that the yield of solid products in the gaseous products reached 70%, with benzoic acid and biphenyl accounting for more than 80%.

[0087] After the depolymerization reaction is complete, the non-gaseous substances in the containment chamber of reaction vessel 1 are solid carbon and liquid gallium indium tin (GaInT) metal. These are separated by the solid-liquid separation mechanism 9, and the solid carbon and liquid GaInT metal are collected separately. The solid carbon can be used to prepare activated carbon, and the separated liquid GaInT metal can be reused for the depolymerization of plastics, achieving recycling.

[0088] When depolymerizing PP plastic, it is first pretreated. Specifically, the PP plastic is first crushed to make the particle size less than 3 mm; then it is placed in an ultrasonic cleaner with water as the cleaning solution and cleaned for 15 minutes to remove surface oil and impurities; then it is placed in a vacuum drying oven at 75 degrees Celsius and dried for three hours to obtain the pretreated PP plastic.

[0089] Then, the pretreated PP plastic and gallium indium liquid metal were added to the containment chamber of reaction vessel 1, with a mass ratio of PP plastic to gallium indium liquid metal of 6:1. The microwave generator and electromagnetic induction generator were activated, enabling the microwave generator to produce 2.45 GHz microwaves, and the power of the microwave generator was adjusted to 1200 watts. The electromagnetic induction generator was also activated, enabling it to produce an 80 kHz alternating magnetic field, and the power of the electromagnetic induction generator was adjusted to 900 watts.

[0090] During the depolymerization reaction, temperature sensing element 11 and pressure sensing element 12 monitor the temperature and pressure inside the containment chamber of reaction vessel 1 in real time. Based on the temperature and pressure inside the containment chamber of reaction vessel 1, controller 7 controls the power and operating time of the microwave generator and electromagnetic induction generator, thereby maintaining the temperature inside the containment chamber of reaction vessel 1 at approximately 630 degrees Celsius and the pressure inside the containment chamber at 0.4 MPa. After the depolymerization reaction has lasted for 25 minutes, the microwave generator and electromagnetic induction generator are turned off, stopping the depolymerization reaction.

[0091] During the depolymerization reaction, gaseous products gradually enter the condensation mechanism 6, while non-gaseous substances remain in the containment chamber of the reaction vessel 1. As the gaseous products pass through the condensation mechanism 6, condensable gases condense into solids and remain in the condensation mechanism 6, while non-condensable gases can flow to the gas collection mechanism 8, thus separating the condensable and non-condensable gases from the gaseous products. Testing revealed that the liquid formed from the condensable gases is light fuel oil, with a yield of 42% and an octane number greater than 75; the non-condensable gases are combustible gases, primarily composed of methane and ethylene, with a calorific value of 48 MJ / kg.

[0092] After the depolymerization reaction is complete, the non-gaseous substances in the containment chamber of reaction vessel 1 are solid carbon and liquid gallium indium metal. These are separated by the solid-liquid separation mechanism 9, and the solid carbon and liquid gallium indium metal are collected separately. The solid carbon can be used to prepare activated carbon, and the separated liquid gallium indium tin metal can be reused for the depolymerization of plastics, achieving recycling.

[0093] When depolymerizing PVC plastic, it is first pretreated. Specifically, the PVC plastic is first crushed to make the particle size less than 4 mm; then soaked in dilute hydrochloric acid solution for two hours to remove surface metallic impurities; then rinsed with clean water until neutral; finally placed in a constant temperature drying oven at 85 degrees Celsius for 2.5 hours to obtain pretreated PVC plastic.

[0094] Then, the pretreated PVC plastic and indium tin liquid metal are added to the containment chamber of reaction vessel 1, with a mass ratio of PVC plastic to indium tin liquid metal of 7:1. The microwave generator and electromagnetic induction generator are activated, enabling the microwave generator to produce 2.45 GHz microwaves, and the power of the microwave generator is adjusted to 1100 watts. The electromagnetic induction generator is activated to produce a 60 kHz alternating magnetic field, and the power of the electromagnetic induction generator is adjusted to 850 watts.

[0095] During the depolymerization reaction, temperature sensing element 11 and pressure sensing element 12 monitor the temperature and pressure inside the containment chamber of reaction vessel 1 in real time. Based on the temperature and pressure inside the containment chamber of reaction vessel 1, controller 7 controls the power and operating time of the microwave generator and electromagnetic induction generator, thereby maintaining the temperature inside the containment chamber of reaction vessel 1 at approximately 620 degrees Celsius and the pressure inside the containment chamber at 0.35 MPa. After the depolymerization reaction has lasted for 32 minutes, the microwave generator and electromagnetic induction generator are turned off, stopping the depolymerization reaction.

[0096] Because PVC plastic contains chlorine, special attention must be paid to controlling the temperature and pressure during the depolymerization reaction to prevent the generation of excessive harmful gases.

[0097] During the depolymerization reaction, gaseous products gradually enter the condensation mechanism 6, while non-gaseous substances remain in the containment chamber of the reaction vessel 1. As the gaseous products pass through the condensation mechanism 6, condensable gases condense into solids and remain in the condensation mechanism 6, while non-condensable gases can flow to the gas collection mechanism 8, thus separating the condensable and non-condensable gases from the gaseous products. Testing revealed that the liquid formed from the condensable gases is light fuel oil, with a yield of 38%, requiring further dechlorination before use. The non-condensable gases are combustible gases; the corrosive hydrogen chloride gas produced during pyrolysis can be effectively absorbed by an aqueous solution, resulting in purified combustible gas with a calorific value of 45 MJ / kg.

[0098] After the depolymerization reaction is complete, the non-gaseous substances in the containment chamber of reaction vessel 1 are solid carbon and liquid indium tin metal. These are separated by the solid-liquid separation mechanism 9, and the solid carbon and liquid indium tin metal are collected separately. The solid carbon contains a small amount of chlorine, which can be removed through chemical treatment and used in industrial adsorption. The separated liquid indium tin metal can be reused for the depolymerization of plastics, achieving recycling.

[0099] When depolymerizing hybrid plastics whose main components are polystyrene and polyurethane, the hybrid plastics are first pretreated. Specifically, the hybrid plastics are first sorted to remove impurities such as metals, paper, and glass; then, the hybrid plastics are crushed; next, they are washed in an alkaline detergent solution to remove surface stains; then, they are rinsed with clean water; finally, they are dried in a 90-degree Celsius drying oven for 3.5 hours to obtain the pretreated hybrid plastics.

[0100] Then, the pretreated hybrid plastic and molten gallium indium tin lead (CIDT) metal were added to the containment chamber of reaction vessel 1, with a mass ratio of hybrid plastic to CIDT liquid metal of 8:1. The microwave generator and electromagnetic induction generator were activated, enabling the microwave generator to produce 2.45 GHz microwaves, and the power of the microwave generator was adjusted to 1300 watts. The electromagnetic induction generator was also activated, enabling it to produce a 70 kHz alternating magnetic field, and the power of the electromagnetic induction generator was adjusted to 950 watts.

[0101] During the depolymerization reaction, the temperature detection element 11 and the pressure detection element 12 monitor the temperature and pressure inside the containment chamber of the reaction vessel 1 in real time. The controller 7 controls the power and working time of the microwave generator and the electromagnetic induction generator according to the temperature and pressure inside the containment chamber of the reaction vessel 1, thereby controlling the temperature inside the containment chamber of the reaction vessel 1 at about 660 degrees Celsius and the pressure inside the containment chamber of the reaction vessel 1 at 0.55 MPa. The depolymerization reaction lasts for 40 minutes to ensure that the mixed plastics with complex components are fully depolymerized.

[0102] During the depolymerization reaction, gaseous products gradually enter the condensation mechanism 6, while non-gaseous substances remain in the containment chamber of the reaction vessel 1. As the gaseous products pass through the condensation mechanism 6, condensable gases condense into solids and remain in the condensation mechanism 6, while non-condensable gases can flow to the gas collection mechanism 8, thus separating the condensable and non-condensable gases from the gaseous products. Testing revealed that the liquid formed by the condensation of the condensable gases consists of various monomeric chemicals, primarily styrene and polyols, with a total yield of 50%. The non-condensable gases are combustible gases with a calorific value of 50 MJ / kg.

[0103] After the depolymerization reaction is complete, the non-gaseous substances in the containment chamber of reaction vessel 1 are solid carbon and liquid gallium indium tin lead (GaInTL) metal. These are separated by the solid-liquid separation mechanism 9, and the solid carbon and liquid GaInTL metal are collected separately. The solid carbon can be used as a raw material for preparing carbon nanomaterials, and the separated liquid GaInTL metal can be reused for the depolymerization of plastics, achieving recycling.

[0104] In summary, the plastic depolymerization device provided by this utility model embodiment can combine the heating technologies of two electromagnetic waves, namely microwaves of a first preset frequency and alternating magnetic fields of a second preset frequency, with the unique properties of liquid metal, to greatly improve the depolymerization efficiency of plastics. Compared with the technical solutions that only use microwave heating to pyrolyze plastics or only use electromagnetic induction heating of liquid metal to pyrolyze plastics, the depolymerization time can be shortened by 30% to 50%.

[0105] Moreover, the plastic depolymerization device provided in this embodiment of the present invention can depolymerize more fully and uniformly, reduce the occurrence of macromolecular residues and side reactions, thereby improving the yield and quality of light fuel oil, combustible gas, etc. in the depolymerization products. The purity of light fuel oil can be increased by 20% to 30%, and the calorific value of combustible gas can be increased by 15% to 25%.

[0106] The plastic depolymerization device provided in this embodiment of the present invention achieves efficient energy utilization, avoiding energy waste caused by insufficient energy utilization in technical solutions that only use microwave heating to pyrolyze plastics or only use electromagnetic induction heating of liquid metal to pyrolyze plastics. The overall energy consumption is reduced by 15% to 25%.

[0107] For high-melting-point, structurally complex waste plastics that are difficult to process using traditional methods, such as engineering plastics and specialty plastics, the plastic depolymerization device provided in this embodiment can effectively depolymerize, thus broadening the types and scope of waste plastic treatment.

[0108] The plastic depolymerization device provided in this embodiment reduces the generation of harmful substances, such as dioxins, during plastic processing, and the depolymerization products can be utilized as resources, meeting the requirements of green environmental protection and sustainable development.

[0109] On the other hand, this utility model also provides a plastic depolymerization method based on the plastic depolymerization apparatus provided in any of the above embodiments. The plastic depolymerization method described below can be referred to in correspondence with the plastic depolymerization apparatus described above.

[0110] like Figure 2 As shown, the plastic depolymerization method provided in this embodiment of the present invention includes steps 110 to 120.

[0111] Step 110: Add the plastic to be treated and the liquid metal to the containment chamber of the reaction vessel, and mix the plastic to be treated and the liquid metal evenly.

[0112] The liquid metal is mixed evenly with the plastic to be treated. The liquid metal has excellent thermal conductivity, and its uniform distribution among the plastics is beneficial for the uniform heating of the plastics.

[0113] Specifically, the plastic to be treated can be mixed with liquid metal by stirring so that the liquid metal can be evenly adhered to the surface of the plastic to be treated.

[0114] Step 120: Radiate microwaves of a first preset frequency into the containment chamber of the reaction vessel to cause the liquid metal to undergo arc discharge and ionize the gas in the containment chamber to form plasma. At the same time, radiate an alternating magnetic field of a second preset frequency into the containment chamber of the reaction vessel to generate eddy currents in the liquid metal in the containment chamber of the reaction vessel.

[0115] The microwaves at the first preset frequency induce an electric arc discharge in the liquid metal within the chamber of reaction vessel 1, thereby ionizing the gas within the chamber to form plasma. The high temperature and highly reactive plasma interact with the plastic molecules, instantly disrupting the plastic molecular structure, lowering the activation energy of the depolymerization reaction, and causing the plastic molecular chains to initially break. The alternating magnetic field at the second preset frequency generates eddy currents in the liquid metal within the chamber of reaction vessel 1. Based on the eddy current effect, a large amount of heat is generated, which can rapidly raise the temperature of the plastic to be treated, further promoting the breaking of plastic molecular chains and the depolymerization reaction.

[0116] This configuration, through the synergistic effect of microwaves at a first preset frequency and alternating magnetic fields at a second preset frequency, significantly improves the depolymerization efficiency of plastics. Furthermore, the excellent thermal conductivity of liquid metal, and its uniform distribution among the plastics being treated, promotes even heating and thorough depolymerization, thus resolving the issues of low pyrolysis efficiency and incomplete pyrolysis in related technologies for treating waste plastics.

[0117] In the plastic depolymerization method provided in this embodiment of the utility model, before step 110, the plastic to be treated needs to be pretreated by crushing, cleaning and drying to remove impurities and cleaning agents from the surface of the plastic to be treated and reduce the particle size of the plastic to be treated.

[0118] During the depolymerization process, the gaseous products in the containment chamber of the reaction vessel 1 need to be output in real time, and the gaseous products are condensed by the condensation mechanism 6 to separate the non-condensable gases and condensable gases, thereby obtaining combustible gases and light fuel oil.

[0119] After the depolymerization reaction is completed, the non-gaseous substances in the containment chamber of reaction vessel 1 need to be separated into solid and liquid phases to separate the liquid metal and the solid carbon produced by depolymerization.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A plastic depolymerization device, characterized in that, include: The reaction vessel (1) has a containment chamber, the containment chamber of which is adapted to contain a mixture of plastic and liquid metal to be treated; The microwave generating mechanism is adapted to emit microwaves of a first preset frequency into the containment chamber of the reaction vessel (1), the microwaves being adapted to cause the liquid metal in the containment chamber of the reaction vessel (1) to undergo arc discharge, so as to ionize the gas in the containment chamber of the reaction vessel (1) to form plasma. An electromagnetic induction generating mechanism is adapted to emit an alternating magnetic field of a second preset frequency into the containment chamber of the reaction vessel (1), the second preset frequency being less than the first preset frequency, and the alternating magnetic field being adapted to generate eddies in the liquid metal within the containment chamber of the reaction vessel (1).

2. The plastic depolymerization device according to claim 1, characterized in that, The microwave generating mechanism includes: A microwave generator (2) is adapted to generate microwaves at the first preset frequency, and the microwave generator (2) is disposed outside the reaction vessel (1); A waveguide transmission component (3) is disposed between the microwave generator (2) and the reaction vessel (1), and the waveguide transmission component (3) is adapted to transmit the microwave generated by the microwave generator (2) to the receiving chamber of the reaction vessel (1).

3. The plastic depolymerization device according to claim 1, characterized in that, The electromagnetic induction generating mechanism includes: An induction coil (4) is arranged around the outside of the receiving chamber of the reaction vessel (1); A power source is electrically connected to the induction coil (4), and the power source is adapted to input alternating current into the induction coil (4).

4. The plastic depolymerization apparatus according to any one of claims 1-3, characterized in that, The first preset frequency is 300 MHz to 300 GHz, and the second preset frequency is 20 kHz to 300 kHz.

5. The plastic depolymerization device according to claim 1, characterized in that, Also includes: The pretreatment unit (5) is adapted to pretreat the plastic to be treated, the pretreatment including at least one of crushing, washing and drying.

6. The plastic depolymerization device according to claim 1, characterized in that, Also includes: A condensing mechanism (6) is connected to the receiving chamber of the reaction vessel (1). The condensing mechanism (6) is adapted to condense the condensable gas in the gaseous products output from the receiving chamber of the reaction vessel (1) into a liquid or solid. A gas collection mechanism (8) is connected to the condensation mechanism (6), and the gas collection mechanism (8) is adapted to collect non-condensable gases in the gaseous products; A solid-liquid separation mechanism (9) is connected to the containment chamber of the reaction vessel (1), and the solid-liquid separation mechanism (9) is adapted to separate solid and liquid substances in the non-gaseous substances in the containment chamber of the reaction vessel (1).

7. The plastic depolymerization apparatus according to claim 6, characterized in that, Also includes: A liquid metal supply mechanism is connected to the containment chamber of the reaction vessel (1), and the liquid metal supply mechanism is adapted to supply the liquid metal to the containment chamber of the reaction vessel (1).

8. The plastic depolymerization device according to claim 7, characterized in that, The liquid metal supply mechanism includes: A spray head (10) is disposed at the top of the receiving chamber of the reaction vessel (1); A liquid metal storage tank, suitable for containing the liquid metal, is connected to the spray head (10) via a connecting pipe. A power pump is installed in the connecting pipeline, and the power pump is adapted to pump the liquid metal in the liquid metal storage tank to the spray head (10). A flow meter is installed in the connecting pipeline, and the flow meter is adapted to measure the flow rate of the liquid metal in the connecting pipeline.

9. The plastic depolymerization device according to claim 1, characterized in that, The reaction vessel (1) is equipped with a stirring mechanism, which is adapted to stir the mixture of the plastic to be treated and the liquid metal.

10. The plastic depolymerization apparatus according to claim 1, characterized in that, Also includes: A temperature sensing element (11) is disposed in the reaction vessel (1), and the temperature sensing element (11) is adapted to detect the temperature inside the containment chamber of the reaction vessel (1); A pressure detection element (12) is disposed in the reaction vessel (1), and the pressure detection element (12) is adapted to detect the pressure in the containment chamber of the reaction vessel (1); The controller (7) is electrically connected to the temperature detection element (11), the pressure detection element (12), the microwave generating mechanism and the electromagnetic induction generating mechanism. The controller (7) is adapted to control the operation of the microwave generating mechanism and the electromagnetic induction generating mechanism according to the temperature and pressure in the containment chamber of the reaction vessel (1).

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